Clutch assembly including calcined kaolin clay wet friction material with improved durability

Abstract

A clutch assembly for a motor vehicle drivetrain includes a rigid support and a wet friction material fixed to a surface of the rigid support. The wet friction material includes a base material including a matrix of fibers and filler particles embedded in the matrix of fibers; and a binder embedded in the base material. The base material includes, by weight percent, 30-55% cellulose fibers and 10-50% calcined kaolin clay. The base material also includes at least one of 1-20% graphite having a mean particle size of 35 to 85 microns, 20-40% diatomaceous earth in combination with the binder being tung modified phenolic resin, 5-20% chopped aramid fibers, or 5-20% of novoloid fibers.

What is claimed is: 
     
         1 . A clutch assembly for a motor vehicle drivetrain comprising:
 a rigid support; and   a wet friction material fixed to a surface of the rigid support, the wet friction material comprising:
 a base material including a matrix of fibers and filler particles embedded in the matrix of fibers; and 
 a binder embedded in the base material, 
 the base material comprising, by weight percent:
 30-55% cellulose fibers; 
 10-50% calcined kaolin clay; and 
 at least one of:
 1-20% graphite having a mean particle size of 35 to 85 microns; 
 20-40% diatomaceous earth in combination with the binder being tung modified phenolic resin; 
 5-20% chopped aramid fibers; or 
 5-20% of novoloid fibers. 
 
 
   
     
     
         2 . The clutch assembly as recited in  claim 1  wherein the base material comprises, by weight percent:
 40-55% cellulose fibers; 
 20-49% calcined kaolin clay; and 
 1-20% graphite having a mean particle size of 35 to 85 microns. 
 
     
     
         3 . The clutch assembly as recited in  claim 2  wherein the base material comprises, by weight percent:
 45-55% cellulose fibers; 
 35-45% calcined kaolin clay; and 
 5-15% graphite having a mean particle size of 35 to 85 microns. 
 
     
     
         4 . The clutch assembly as recited in  claim 1  wherein the base material comprises, by weight percent:
 30-55% cellulose fibers; 
 10-40% calcined kaolin clay; and 
 20-40% diatomaceous earth, 
 the wet friction material including, by weight percent, 31 to 35% of tung modified phenolic resin. 
 
     
     
         5 . The clutch assembly as recited in  claim 4  wherein the base material comprises, by weight percent:
 45-55% cellulose fibers; 
 15-25% calcined kaolin clay; and 
 25-35% diatomaceous earth, 
 the wet friction material including, by weight percent, 31 to 35% of tung modified phenolic resin. 
 
     
     
         6 . The clutch assembly as recited in  claim 1  wherein the base material comprises, by weight percent:
 30-55% cellulose fibers; 
 30-50% calcined kaolin clay; and 
 5-20% chopped aramid fibers. 
 
     
     
         7 . The clutch assembly as recited in  claim 6  wherein the base material comprises, by weight percent:
 45-55% cellulose fibers; 
 35-45% calcined kaolin clay; and 
 5-15% chopped aramid fibers. 
 
     
     
         8 . The clutch assembly as recited in  claim 6  wherein the chopped aramid fibers have a mean length of 2.8 to 3.2 mm. 
     
     
         9 . The clutch assembly as recited in  claim 6  wherein the chopped aramid fibers have a mean diameters of 10 to 45 microns. 
     
     
         10 . The clutch assembly as recited in  claim 1  wherein the base material comprises, by weight percent:
 30-55% cellulose fibers; 
 30-50% calcined kaolin clay; and 
 5-20% novoloid fibers. 
 
     
     
         11 . The clutch assembly as recited in  claim 1  wherein the base material comprises, by weight percent:
 45-55% cellulose fibers; 
 35-45% calcined kaolin clay; and 
 5-15% novoloid fibers. 
 
     
     
         12 . The clutch assembly as recited in  claim 10  wherein the novoloid fibers have a mean length of 0.2 mm to 0.35 mm. 
     
     
         13 . The clutch assembly as recited in  claim 10  wherein the novoloid fibers have a mean diameters of 10 to 45 microns. 
     
     
         14 . The clutch assembly as recited in  claim 1  wherein the wet friction material includes, by weight percent, 31 to 35% of the binder. 
     
     
         15 . The clutch assembly as recited in  claim 14  wherein the binder is tung modified phenolic resin. 
     
     
         16 . A method of making a clutch assembly for a motor vehicle comprising:
 fixing a wet friction material to a surface of a rigid support,   the wet friction material being made by:
 providing a base material; 
 saturating the base material with binder; and 
 curing the binder, 
 the base material comprising, by weight percent:
 30-55% cellulose fibers; 
 10-50% calcined kaolin clay; and 
 at least one of:
 1-20% graphite having a mean particle size of 35 to 85 microns; 
 20-40% diatomaceous earth in combination with the binder being tung modified phenolic resin; 
 5-20% chopped aramid fibers; or 
 5-20% of novoloid fibers. 
 
 
   
     
     
         17 . The method as recited in  claim 16  wherein the binder is tung modified phenolic resin.